In an effort to generally improve one's health, many people regularly exercise on treadmills by walking, jogging, and running along a traveling surface. There have been many improvements and new developments in treadmills over the years, including motorized treadmills. With motorized treadmills the user may adjust the speed of the treadmill belt to the pace he/she wishes to run or walk. Motorized treadmills, however, require sufficient cooling for the circuitry and motor to operate efficiently. Although motorized exercise treadmills have proven to be useful, the treadmills of the prior art incorporate several inherent disadvantages.
One disadvantage of motorized treadmills is that they require electric motors and control systems that create heat that must be removed in order for the treadmill to operate efficiently. Excessive heat in a motorized treadmill will cause the efficiency of the electric motor to decrease as well as electronic control circuitry to overheat. In order to remove the heat produced by the motor and control circuitry treadmills incorporate a cooling fan that is attached to the motor shaft. The amount of cooling provided by the fan, therefore, is directly proportional to the speed of the treadmill belt. A drawback to this cooling system is that at low treadmill speeds the fan may not provide sufficient cooling.
If the motor becomes too hot, it cannot produce enough current to generate a sufficient amount of torque from the motor to drive the treadmill belt. This occurs because the amount of heat generated in the motor is proportional to the amount of current applied to the motor. At high treadmill belt speeds the cooling of the motor is not a problem because the motor shaft is rotating at sufficient revolutions per minute to sufficiently cool the motor. This cooling allows the motor to increase its torque output by increasing its current.
The problem of overheating is especially evident, for instance, when a heavy person is walking (rather than running) on a treadmill. As the weight of the person on the treadmill increases, the amount of torque required to keep the treadmill belt moving at a constant speed increases. Therefore, since the amount of torque generated by a treadmill motor is generally in proportion to the current applied to the motor, and since also the amount of heat generated in the motor is proportional to the amount of current that can be applied to motor, problems arise at low speeds. At low speeds, the cooling fan does not function as effectively, and therefore less current can be applied to the motor, resulting in less torque output from the motor. At high speeds, however, overheating is typically not a problem because the cooling fan, which is mounted on the motor shaft, rotates sufficiently to cool the motor to move the belt.
Another disadvantage with treadmills is that sufficient cooling is not provided for the electronic control circuitry required for motorized treadmills. This is especially true, if the electronic components are being cooled by a fan located on the motor shaft. Since the amount of cooling available is directly proportional to the motor shaft speed, the electronic circuitry does not get sufficient cooling while the treadmill belt is moving at lower speeds. Electronic circuitry operates at a better efficiency when it is cooler. Additionally, the hotter the circuitry becomes, the hotter the motor will become due to the proximity of the circuitry to the motor. The heating from the circuitry causes the motor to generate even less torque because of this additional heating source.
It would therefore be advantageous to overcome the limitations in the prior art treadmills, it would be desirable to provide a cooling system that would sufficiently cool treadmill motors and electronic components at low speeds such that that the motor may generate more current resulting in higher torque output to move the treadmill belt at constant speeds.